The present invention relates to pipelines and, more part to a permanent replacement pipe section for a defective pipeline.
Replacement of a leaking or otherwise defective pipeline requires first that the defect be located, followed by excavation of a "bell" hole around the defect large enough to remove the defective section of pipeline.
Currently available permanent replacement pipe sections utilized in the repair of leaking or otherwise defective pipelines require not only sufficient excavation to remove the defective section of pipe but also excavation of approximately 100 to 150 additional feet around each open end of the pipeline to allow space for the installation of flanges to enable attachment of the replacement section of pipe to the open ends of the pipeline. The larger the diameter of the pipeline, the more excavation is required. These prior art replacement pipe sections also require that the length of pipeline inserted into place be the exact length as the pipeline removed.
The above described replacement pipe sections suffer from the disadvantage that the additional excavation around each of the open ends of the pipeline to expose a sufficient length of pipe to allow for installation of the necessary flanges requires a significant amount of labor and is thus costly. In addition, if the repair section of pipeline is not cut to be exactly the same length as the length of pipeline removed, it may be necessary to scrap the length of pipeline or to use additional fittings or flanges. This may result in additional labor and materials being used and may provide a less reliable connection of the new section of pipeline.
Also available in the prior art are external bolt-on patches which can be used to temporarily repair a defective pipeline. However, these bolt-on patches suffer from the disadvantage that the pipeline may continue to erode under the patch and most likely a permanent patch will eventually need to be installed.
It is often advantageous for pipelines to be internally coated with a material that prevents corrosion of the pipeline wall and also prevents the buildup of scale. A problem presented by internally coated lines is that of maintaining the integrity of this internal coating when it is necessary to replace a section of the pipeline. At points where internally coated lines terminate, it is very difficult to maintain the corrosion barrier within the connections.
It is therefore an object of the present invention to provide a replacement pipe section for a defective pipeline that minimizes the amount of excavation that is required to replace the defective section.
It is another object of the present invention to provide a replacement pipe section for a defective pipeline that can be installed in place without the use of flanges.
Another object of the present invention is to provide a replacement pipe section for a defective pipeline that provides a fluid-tight seal between the replacement pipe section and the open ends of the pipeline.
Another object of the invention is to provide a replacement pipe section for a defective pipeline that eliminates the necessity that the replacement pipe section be the exact length as the defective pipe section removed.
A further object of the invention is to provide a replacement pipe section for a defective internally coated pipeline that effectively maintains the integrity of the internal coating and thus is capable of transporting corrosive materials.
A further object of the invention is to provide a replacement pipe section for a defective pipeline that is permanent, easy to install and cost effective.